Is my use of the changed event wrong?

Hi,

I'm using trello to store values so I can use them on another ROBLOX game. I've been using a script called TrelloAPI to use the trello API. It's worked flawlessly and I 100% doubt that that script is at fault here. Anyway, there's a TextBox GUI in the game, and when the text is changed (or preferably after a button is pressed), I'd like 'EndPlaceID' to be the updated text of that textbox. Here's what i've tried:

textbox = game.StarterGui.ScreenGui.Frame.TextBox
textbox.Changed:connect(function()
    local EndPlaceID=textbox.Text
    local ap = require(game.Workspace.TrelloAPI) 
local BoardID = ap:GetBoardID("My Board")
local PlaceID = game.PlaceId

ap:AddList(""..EndPlaceID,BoardID)
local ListID = ap:GetListID(""..EndPlaceID,BoardID)
ap:AddCard("PlaceID",""..PlaceID,ListID) 

end)

Oh and nothing shows up in the output, but when I type something in the textbook, trello doesn't update.

And yes, it did update before I started using the changed bit and when I just made EndPlaceID a string.

Thanks in advance.